Question

The gene I that determines ABO blood groups has three alleles $I^A,I^{B}and{I}^O$ . The correct sequence of dominance of these alleles is

• A. I^A = I^B> I^O
• B. I^A = I^B = I^O
• C. I^A> I^B> I^O
• D. I^A< I^B< I^O

Answer 1

The correct option is A

I^A = I^B> I^O

ABO blood grouping in human beings is controlled by a gene I which has three alleles- $I^A,I^{B}and{I}^O$. Among these, $I^{A}and{I}^B$ are equally dominant indicating codominance, and they are dominant over $I^O$ or i, which is a recessive allele.